Apple has revealed that Vietnamese developer Thuat Nguyen used 400 hacked accounts to promote his own apps. Roughly 40 of the top 50 Books apps were his creation at the height of the issues.
Nguyen’s apps were removed from the App Store because of “violations to the developer Program License Agreement, including fraudulent purchase patterns. Apple will ask more frequently for CCV numbers from credit cards in order to better validate purchases.”
Source: PC World